The goals of the statistical and programming core (Core B) are to provide statistical guidance and programming support for all analyses undertaken in each of the projects. The statistical analysis group is led by Dr. Donna Spiegelman, who has served as statistician for the Health Professionals Follow-up Study since 1990. She is supported by two doctoral-level Junior Statisticians, Drs. John Ritz and Thomas Schlopflocher, and three masters-level junior statistician programmer/ analysts. The doctoral-level statisticians provide statistical support for all the projects, develop new statistical methods as the need arises in the course of ongoing work, and develop statistical software to support new and non-standard methods when required for proper analysis of the data. The masters level statisticians and programmers in Core B perform data base management and data analysis at the direction of project investigators and the collaborating statisticians. In addition, programming support is provided for the identification of cases and controls for analyses of biomarkers in Projects 1, 2, and 3. Core B is also responsible for quality control of all analyses and documentation of data in all reports arising from the Health Professionals Follow-up Study and Pooling Project data.